The Baryonic Tully-Fisher relation: reconciling the observed and predicted slopes under the standard $\Lambda$CDM paradigm

SEBASTIÁN GUROVICH; KENNETH FREEMAN; HELMUT JERJEN; STAVELEY-SMITH, LISTER; IVANIO PUERARI

ASTRONOMICAL JOURNAL

IOP Publishing Limited 2009

Año: 2010 vol. 140 p. 663 - 676

0004-6256

We present the results of a baryonic Tully-Fisher relation (BTFR) study for a local sample of relatively isolated disk galaxies. We derive a BTFR with a slope near $3$ measured over about $4$ dex in baryon mass for our combined extrm{H,scriptsize{I}} and bright spiral disk samples. This BTFR is significantly flatter and has less scatter than the TFR (stellar mass only) with its slope near $4$ reported for other samples and studies.  A BTFR slope of 3 is in better agreement with the expected slope from simple $Lambda$CDM cosmological simulations that include both stellar and gas baryons. The scatter in the TFR/BTFR appears to depend on $W_{20}$: galaxies that rotate slower have more scatter. The atomic gas--to--stars ratio shows a break near $W_{20} = 250$ km/s, probably associated with a change in star formation efficiency. In contrast the absence of such a break in the BTFR suggests that this relation was probably set at the main epoch of baryon dissipation rather than as a product of later galactic evolution.